Gezondheidsbewaking, medische triage en risicostratificatie · Gezondheidsbewaking, medische triage...
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Gezondheidsbewaking, medische triage en risicostratificatie
Dick Heederik
IRAS, Divisie Milieu-epidemiologie, Universiteit Utrecht
Gezondheidsbewaking, medische triage en risicostratificatie
Dick Heederik
epidemiologie, Universiteit Utrecht
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Gezondheidsbewakingssysteem Gezondheidsbewakingssysteem – bakkerijbranche
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Voorgeschiedenis
� Onderzoek naar allergie bij bakkers van Houba
(1996) en meerdere vervolgsurveys:
� Sensibilisatie tarwemeel en enzymen>10-15% van de
werknemers
� Respiratoire klachten en BHR komen veelvuldig voor
� Advies van de Gezondheidsraad over mogelijkheden
voor grenswaarde voor tarwemeelstof
� Voorstel grenswaarde commissie GBBS
Gezondheidsraad 0,5 mg/m3 8-uur tgg
� Voorstel advieswaarden allergenen GR 2008
Voorgeschiedenis
Onderzoek naar allergie bij bakkers van Houba
15% van de
Respiratoire klachten en BHR komen veelvuldig voor
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Advies van de Gezondheidsraad over mogelijkheden
Voorstel grenswaarde commissie GBBS
Voorstel advieswaarden allergenen GR 2008
Grenswaarde, waarom gezondheidsbewaking
� Grenswaarde beperkt het risico op allergie, maar elimineert het niet volledig
� Gebaseerd op berekening van ‘acceptabel’ risiconiveau (gezondheidsraad)risiconiveau (gezondheidsraad)
Wheat allergen exposure [µg EQ/m3]
0,001 0,01 0,1 1 10 100 1000
P(S
ensitiz
ation)
0
20
40
60
80
100
Heederik & Houba 2001
traditional bakers
industrial bakers
bakery supplies
flour mill workers
Grenswaarde, waarom gezondheidsbewaking
Grenswaarde beperkt het risico op allergie, maar elimineert het niet volledig
Gebaseerd op berekening van ‘acceptabel’ risiconiveau (gezondheidsraad)
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risiconiveau (gezondheidsraad)
Dus een convenant …
� Afspraken over voorlichting werkgevers en werknemers
� Stofbeheersingsplan en praktijkhandboek om stofarme werkwijzen te stimulerenwerkwijzen te stimuleren
� Blootstellingsreductie voor industriele bakkers, meelfabrieken en de bakkerijgrondstoffen industrie (reductie piekblootstellingen met 50%)
� Evaluatie van maatregelen
� Gezondheidsbewaking onder ‘blootgestelden’
Dus een convenant …
Afspraken over voorlichting werkgevers en werknemers
Stofbeheersingsplan en praktijkhandboek om stofarme werkwijzen te stimuleren
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werkwijzen te stimuleren
Blootstellingsreductie voor industriele bakkers, meelfabrieken en de bakkerijgrondstoffen industrie (reductie piekblootstellingen met 50%)
Evaluatie van maatregelen
Gezondheidsbewaking onder ‘blootgestelden’
Surveillance
� Medical surveillance is the analysis of health information that may be occurring in the workplace and require targeted prevention. Surveillance can include both populationgroup-based activities and individual activities.
� The individual-oriented activities are often referred to as worker screening and monitoring functions worker screening and monitoring functions
� Aims: secondary prevention>early detection>subsequent management
� Questionnaires, serology/skin prick testing, (BHR)
� Protocols available for different industrial sectors (Platinum IPA; Laboratory Animal Workers)
Surveillance
Medical surveillance is the analysis of health information that may be occurring in the workplace and require targeted prevention. Surveillance can include both population- or
based activities and individual activities.
oriented activities are often referred to as worker screening and monitoring functions worker screening and monitoring functions
Aims: secondary prevention>early detection>subsequent
Questionnaires, serology/skin prick testing, (BHR)
Protocols available for different industrial sectors (Platinum IPA; Laboratory Animal Workers)
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Prediction research and surveillance
� Specific use of surveillance tools has
� Detection or diagnosis of diseasetesttest
� Prediction research a multivariate approach in design and analysis that accounts for mutual dependence between different test results. The information of every item can then be translated into a predicted probability of the chosen outcome.
Prediction research and surveillance
of surveillance tools has not been described
disease seldom on the basis of one
a multivariate approach in design and analysis that accounts for mutual dependence between different test results. The information of every item can then be translated into a predicted probability of the chosen
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Alternative approaches
� Triage or risk stratification: predict sensitization (ideally OA, OR)
� short questionnaire (scanned or internet based) and a diagnostic model for sensitization (phase I)
� referral to occupational health service or specialized clinic (phase II)
� results reported back to occupational health service for (exposure) intervention (phase III)
Alternative approaches
Triage or risk stratification: predict sensitization (ideally OA, OR)
short questionnaire (scanned or internet based) and a diagnostic model for sensitization (phase I)
referral to occupational health service or specialized clinic (phase
results reported back to occupational health service for (exposure) intervention (phase III)
MODEL DEVELOPMENT(Editorial Suarthana Occup Env Med 2009 and J Clin Epid 2009)
Available data• 391 Dutch bakers (22.1% sensitised)• Questionnaire items (>75) and detailed• Logistic regression analyses with backward• Reference: IgE sensitization to wheat
Model PerformanceModel Performance• Calibration: the Hosmer–Lemeshow• Discrimination: area under the receiver
(AUC)
Model Validation• Internal validation: bootstrapping procedure• External validation: in new bakers �
MODEL DEVELOPMENT(Editorial Suarthana Occup Env Med 2009 and J Clin Epid 2009)
sensitised); Groningen study, 2002detailed exposure data
backward selection methodwheat and or amylase allergens
Lemeshow (H-L) goodness-of-fit test.receiver operating characteristic curve
procedure� Validation study
MODEL DEVELOPMENT
Multivariate Association
Asthma
Rhinitis allergy
Conjunctivitis allergy
During work symptoms
�Formula to calculate predicted probability of sensitization=
1 / (1 + EXP( - ( - 2.32 + 0.92 *asthma + 0.90 *rhinitis + 0.46* conjunctivitis + .62 *
during work symptom))) .
MODEL DEVELOPMENT
OR (95% CI)
2.7 (1.3 to 5.8)
2.7 (1.6 to 4.6)
1.6 (1.0 to 2.8)
2.0 (1.1 to 3.4)
Formula to calculate predicted probability of sensitization=
2.32 + 0.92 *asthma + 0.90 *rhinitis + 0.46* conjunctivitis + .62 *
during work symptom))) .
Diagnostic model as score chart
Predictors
Asthma symptoms
Rhinitis symptoms
Conjunctivitis symptoms
During work allergic symptomsDuring work allergic symptoms
Sum scores
Sum score 0 1
Predicted probability (%)
9 14
Diagnostic model as score chart
Value Score
+ 2
+ 2
+ 1
During work allergic symptoms + 1.5During work allergic symptoms + 1.5
Sum scores Max 6.5
2 3.5 4.5 5.5 6.5
20 31 42 53 64
�Phase I
Health Surveillance system
Probability of sensitization to wheat and/or amylase allergenswas calculated for every baker using the diagnostic model
Questionnaires were distributed to and returnedby bakers in the health surveillance program
�Phase II Will be enrolled inthe next surveillance
Lowprobability group(sum scores 0-1)
Refer to occupationalhealth service
Mediumprobability group
(sum scores 1.5-3.0)
Health Surveillance system
Probability of sensitization to wheat and/or amylase allergenswas calculated for every baker using the diagnostic model
Questionnaires were distributed to and returnedby bakers in the health surveillance program
Refer to occupationalhealth service
Mediumprobability group
(sum scores 1.5-3.0)
Refer to clinic
Highprobability group
(sum scores >= 3.5)
Calibration and discrimination
30
40
50
0
10
20
30
0-10.0 10.1-20.0 20.1-30.0 > 30.0
%
Average predicted probability Observed proportion
�False positives versus false negatives
Calibration and discrimination
0.6
0.8
1
sensitiv
ity
0
0.2
0.4
0 0.2 0.4 0.6 0.8 1
1 - specificity
sensitiv
ity
Development set Referrence
�(ROC) area 0.73 (95%CI 0.67 to 0.79)
False positives versus false negatives
Participation in Phase I
Traditional bakeryEmployers n=1189
Workers n=3225 (60%)
Industrial bakeryEmployers n=74
Workers n=1405 (80%)
Participation in Phase Ibakers n= 5,348
Complete Questionnaire
n=2686 (83%)
Blood samples n=399
Workers n=3225 (60%)
Complete Questionnaire
n=1124 (80%)
Blood samples n=214
Workers n=1405 (80%)
�Validation study sample
Participation in Phase I
Flour millingEmployers n=10
Workers n=398 (58 %)
Baking productsEmployers n=13
Workers n=320 (58 %)
Participation in Phase Ibakers n= 5,348
Complete Questionnaire
n=344 (86%)
No blood samples
Workers n=398 (58 %)
Complete Questionnaire
n=260 (81%)
No blood samples
Workers n=320 (58 %)
Reasons for non
The study was not important
No particular reason
Afraid that their employee would use
results against them
�N=86 bakers who did not returned short questionnaire, but participated in the validation study
Did not receive the questionnaire
Forgot to send back the questionnaire
and or lost it
Did not feel like to participate because
did not have any symptoms
Reasons for non-response*
0,1
0,06
0,03
N=86 bakers who did not returned short questionnaire, but participated in the validation study
0,33
0,33
0,29
0 0,05 0,1 0,15 0,2 0,25 0,3 0,35
Model ApplicationModel Application
Model ApplicationModel Application
Model ApplicationModel Application
Results Phase III clinic (Meijer et al., ERJ 2010)
� Applied short (serology and BHR) and long diagnostic protocol
� 40% wheat, 14% α-amylase � App. 50% of high scorers has BHR, a larger group has mild
BHRBHR� 35% has work related asthma
� 20% work exacerbated asthma� 15% work related allergic asthma
� Large proportion has severe work related rhinitis
�Misdiagnosis by GPs is a major issue (in app 30% work related cause is not suspected while being treated)
Results Phase III clinic (Meijer et al., ERJ 2010)
Applied short (serology and BHR) and long diagnostic
amylase sensitizedApp. 50% of high scorers has BHR, a larger group has mild
35% has work related asthma
Large proportion has severe work related rhinitis
Misdiagnosis by GPs is a major issue (in app 30% work related cause is not suspected while being treated)
Intervention
� Intervention:
� Outplacement (Taskforce report ERJ and Eur Resp Review 2012)
� Exposure reduction in case of occupational allergy and occupational asthma? Vandenplas et al., Management of occupational asthma: cessation or reduction of exposure? A systematic review of available cessation or reduction of exposure? A systematic review of available evidence. ERJ 2011
Intervention
Outplacement (Taskforce report ERJ and Eur Resp Review 2012)
Exposure reduction in case of occupational allergy and occupational Management of occupational asthma:
cessation or reduction of exposure? A systematic review of available cessation or reduction of exposure? A systematic review of available
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Wetenschappelijke acceptatie van het gevolgde model?
� GR Advies. Preventie van werkgerelateerde luchtwegallergieën: advieswaarden en periodieke screening. Den Haag, 2008.
� Baur et al., for the ERS Taksforce. management of work-related asthma. ERJ 2012
� Wilken et al., for the ERS Taskforce. of medical screening and surveillance? Eur Resp Rev 2012
Wetenschappelijke acceptatie van het gevolgde model?
GR Advies. Preventie van werkgerelateerde luchtwegallergieën: advieswaarden en periodieke screening.
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Baur et al., for the ERS Taksforce. Guidelines for the related asthma. ERJ 2012
Wilken et al., for the ERS Taskforce. What are the benefits of medical screening and surveillance? Eur Resp Rev 2012
Praktische aspecten en vervolg
� Motivatie populatie vraagt ‘outreaching benadering’
� Communicatie tussen partijen en betrokkenen van groot belang
� Rol bedrijfsarts problematisch (doorverwijzing (expertise) en interventie (afwezigheid, of indien aanwezig positie en borging)interventie (afwezigheid, of indien aanwezig positie en borging)
� Belang voor de werknemers is groot
� Prognose
� Ontbreken valide diagnose
� Ineffectieve behandeling huisarts
� Mogelijkheden van interventie
� Toekomst: diagnostische regels voor beroepsastma (reductie fout positieven en negatieven)
Praktische aspecten en vervolg
Motivatie populatie vraagt ‘outreaching benadering’
Communicatie tussen partijen en betrokkenen van groot belang
Rol bedrijfsarts problematisch (doorverwijzing (expertise) en interventie (afwezigheid, of indien aanwezig positie en borging)
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interventie (afwezigheid, of indien aanwezig positie en borging)
Belang voor de werknemers is groot
Toekomst: diagnostische regels voor beroepsastma (reductie fout
Ten slotte: Doorrekenen “health impact”(Warren et al., Occup Env Med 2009; Meijster et al., Occup Env Med
2010)
Ten slotte: Doorrekenen “health impact”(Warren et al., Occup Env Med 2009; Meijster et al., Occup Env Med
2010)
Doorrekenen “health impact”Doorrekenen “health impact”
Kosten baten analyse reguliere interventie versus gezondheidbewaking en interventie
(Meijster et al., Occup Env Med 2011)
� Reguliere interventie leidde tot 20 jaar voor een populatie van 10 000 werknemers. Implementatie was kosten effectief voor alle belanghebbenden. belanghebbenden.
� Voor een gezondheidsbewakingssysteem, baten die resulteerden van een beperkte ziektelast werden geschat op €44 659 352
Kosten baten analyse reguliere interventie versus gezondheidbewaking en interventie
(Meijster et al., Occup Env Med 2011)
Reguliere interventie leidde tot €16 848 546 aan baten over 20 jaar voor een populatie van 10 000 werknemers. Implementatie was kosten effectief voor alle
Voor een gezondheidsbewakingssysteem, baten die resulteerden van een beperkte ziektelast werden geschat op
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